The AC control unit is powered from 12V. The thermostat tells it what to do. Check out page 9: http://www.dometic.com/FileOrganizer...llation_EN.pdf
We run 12Vdc and 120Vac through the roof to the AC opening. So if the 12Vdc is dead, the control unit inside the AC would not be functioning. we use the Brisk Air AC's on the class C line.

The AC control unit is powered from 12V. The thermostat tells it what to do. Check out page 9: http://www.dometic.com/FileOrganizer...llation_EN.pdf
We run 12Vdc and 120Vac through the roof to the AC opening. So if the 12Vdc is dead, the control unit inside the AC would not be functioning. we use the Brisk Air AC's on the class C line.

Thank you John.
I had no idea the Class C units had a "Comfort Controller" that has a separate 12VDC run (fused at 3 amps). My Coleman Mach III is not set up that way.

I see the fan motor is twelve volts to circulate air when traveling down the road unlike the trailer unit which have no reason to run the fan when no bodys in the trailer unlike the motorhome which people occupy the whole unit and need to keep cool air in whole unit.

Thank you John.
I had no idea the Class C units had a "Comfort Controller" that has a separate 12VDC run (fused at 3 amps). My Coleman Mach III is not set up that way.

Where is that 3 amp fuse located?

Do all Motor Homes have this type system?

What trailers have this unit?

The 3 Amp fuse is built inside the AC module also. We supply that 12Vdc with the same circuit we wire for all of our roof vent/fans. I believe it is more just to power a relay inside than anything...I've never dove too far into it other than knowing what we have to provide the AC module in order for the AC to work correctly.
I am uncertain who all uses the Brisk Air AC's other than us. We don't have set standards even within FR, so each division and product is free to find what works best for them.
Also, I forgot I was in a trailer thread. oops. I didn't mean to muddy up the waters with other product info. Please forgive me.

Also, I forgot I was in a trailer thread. oops. I didn't mean to muddy up the waters with other product info. Please forgive me.

No, you are quite correct!

It is not a trailer thread. It is in General Tech.

This happens quite a lot actually and a hazard of putting "generic" tech support by appliance in one place. Sometimes I make assumptions based on my experience (OK, it happens a lot) with trailers and assume it applies to everyone. I am learning.

I had no idea motorhomes could have both AC and DC FEED requirements, since all my trailer air conditioners never did. Lesson learned again.